When you have unlocked the Vampire go to the 'Main' menu and hold L2 + R2 and press L1(2), Triangle(2), Square, L1. If you have entered the code correctly the Vampire MK1 will become unlocked.

Complete the following tasks in the game to unlock the corresponding effect.

Unlock Ace Killer:
Defeat ALL the other Aces in the game to unlock Ace Killer.

Unlock Ace Of Aces:
Get the highest score in ALL the Campaign missions in the game.

Unlock ALL Campaign Missions and Planes:
At the Title menu hold L2 and R2 and enter Square, L1, R1, Triangle, Triangle, R1, L1, Square.

Unlock Invincibility:
During gameplay pause the game and hold L2 and press Square, Triangle, Triangle, Square. Release L2, then hold R2 and quickly press Triangle, Square, Square, Triangle.

Increase Damage of Weapons:
During gameplay pause the game and hold L2 and quickly press L1, L1, R1. Release L2 and then hold R2 and quickly press R1, R1, L1.